Spermatogenic Failure 13

A number sign (#) is used with this entry because of evidence that spermatogenic failure-13 (SPGF13) is caused by homozygous mutation in the TAF4B gene (601689) on chromosome 18q11. One such family has been reported.

For a general phenotypic description and a discussion of genetic heterogeneity of spermatogenic failure, see SPGF1 (258150).

Clinical Features

Ayhan et al. (2014) studied a consanguineous Turkish family in which 4 of 8 brothers were infertile, 3 of whom were azoospermic. The remaining affected brother was oligozoospermic, with a sperm count of 6 million/mL and normal sperm morphology. The brothers had each been married for 23 to 37 years but had no children, except for the oligozoospermic brother, who had 1 child; an unaffected brother had 9 children. Serum levels of luteinizing hormone (LH; 152780), prolactin (176760), and testosterone were normal, but follicle-stimulating hormone (FSH; 136530) level was increased. A diagnosis of nonobstructive azoospermia was made based on the presence of small testicles and elevated FSH.

Molecular Genetics

In a consanguineous Turkish family in which 4 of 8 brothers were infertile but had a normal male karyotype and no microdeletions in the AZF region at Yq11, Ayhan et al. (2014) performed linkage analysis and exome sequencing, following by filtering, to identify homozygosity for a nonsense mutation in the TAF4B gene (R611X; 601689.0001) in the 4 affected brothers. Their fertile brother who had 9 children was heterozygous for the mutation, which was not found in 120 population controls.